This invention provides an improved non-toxic primer mix for small arms center-fire ammunition which is free of metallic oxidizing compounds and of hygroscopic compounds. The need for such a non-toxic primer mix is well established, because there is a great deal of indoor shooting which requires that the air be free of the dust or oxides of any and all toxic elements. Thus, it is highly desirable that all toxic metals be eliminated from the primer mixes which are utilized in the ammunition which is expended in such indoor shooting.
In the past, the primers of small arms ammunition contained mercury, lead, potassium chlorate, antimony, and various other chemicals which were both toxic and corrosive. During the 1930's, these objectionable chemicals were replaced by other materials which were more chemically stable and did not corrode steel gun barrels. These replacement primers contained lead, barium, antimony, and aluminum metallic compounds. They were very stable chemically and were non-corrosive to firearms.
Over the ensuing years, because of environmental and health concerns, the demand has arisen that there be no mercury, lead, barium, antimony, beryllium, cadmium, arsenic, chromium, selenium, tin, or thallium included in such primer mixes. Additional elements which have been considered undesirable by the Environmental Protection Agency (EPA) are zinc and copper and, therefore, they, too, have been included as undesirable components of primers.
Over the preceding years, many attempts have been made to solve the toxicity problems described above and which are still currently being experienced in the field. As a result, a substantial number of U.S. patents have issued, each claiming benefits in performance and, in many instances, with respect to toxicity. None of these patents, to the best of our knowledge, accomplish non-toxicity, in that almost all of them utilize metallic oxidizing compounds which are either toxic or have other undesirable characteristics. For example, U.S. Pat. No. 2,689,788 utilizes ferric styphnate, lead styphnate, barium nitrate, and glass.
U.S. Pat. No. 4,363,679 utilizes zinc peroxide, calcium silicide, magnesium, nickel, and titanium.
U.S. Pat. No. 4,581,082 utilizes strontium nitrate, diazodinitrophenol, tetracene, and a propellant.
U.S. Pat. No. 4,608,102 utilizes DDNP, tetracene, nitrocellulose, aluminum, manganese dioxide, zinc dioxide, and zinc oxide.
U.S. Pat. No. 4,674,409 utilizes DDNP, tetracene, manganese dioxide, and glass.
U.S. Pat. No. 4,675,059 utilizes DDNP, tetracene, manganese dioxide, and glass.
U.S. Pat. No. 4,963,201 utilizes DDNP, tetracene, a propellant, and strontium nitrate.
U.S. Pat. No. 5,167,736 utilizes DDNP, tetracene, a propellant, calcium carbonate, and boron, the latter being at the core of the invention.
U.S. Pat. No. 4,689,185 utilizes DDNP, tetracene, magnanese dioxide and glass.
U.S. Pat. No. 5,216,199 utilizes DDNP, tetracene, strontium nitrate, glass and a suitable propellant.
U.S. Pat. No. 2,409,201 utilizes aluminum zinc oxide and FeCl.sub.3.
U.S. Pat. No. 2,123,691 utilizes barium oxide, manganese, selenium, HgCl, potassium chlorate and carbon.
U.S. Pat. No. 4,566,921 utilizes Hg, nitrotetrozole, potassium chlorate, PbSCN, Sb.sub.2 S.sub.3 and PETN.
U.S. Pat. No. 4,508,580 utilizes barium nitrate, ferric oxide, Mg/Al, strontium, lead oxide and Fe.sub.2 O.sub.2.
U.S. Pat. No. 4,405,392 utilizes sodium styphnate, PBHPO.sub.2, PB(No.sub.3).sub.2 and tetracene.
U.S. Pat. No. 4,376,002 utilizes, among others, ferric oxide, MnO.sub.2 and SnO.sub.2.
U.S. Pat. No. 4,349,612 utilizes zinc oxide and sodium hydroxide, among others.
U.S. Pat. No. 3,625,855 utilizes manganese and zinc oxide.
U.S. Pat. No. 3,320,104 utilizes barium nitrate and aluminum oxide along with barium sulfate and graphite.
U.S. Pat. No. 3,310,569 utilizes lead styphnate along with tetracene, barium nitrate, lead oxide and glass.
U.S. Pat. No. 2,262,818 utilizes DDNP, tetracene and lead nitrate along with glass.
U.S. Pat. No. 3,087,428 utilizes barium nitrate along with lead sulfide.
U.S. Pat. No. 3,257,892 utilizes barium nitrate and lead oxide along with tetracene, PETN and others.
U.S. Pat. No. 3,420,137 utilizes tetracene, PETN, aluminum and styphnate.
U.S. Pat. No. 3,499,386 utilizes barium nitrate and lead oxide as well as ferric oxide.
U.S. Pat. No. 3,321,343 utilizes barium nitrate along with tetracene and others.
U.S. Pat. No. 4,608,102 utilizes DDNP, tetracene, manganese dioxide and zinc dioxide along with others.
U.S. Pat. No. 3,423,259 utilizes calcium silicide and karaya gum.
U.S. Pat. No. 3,348,985 utilizes NH.sub.4 NO.sub.3, potassium nitrate, and other oxides.
U.S. Pat. No. 3,862,866 utilizes potassium chlorate and sucrose.
U.S. Pat. No. 4,363,679 utilizes zinc oxide and calcium silicide.
U.S. Pat. No. 4,247,494 utilizes barium nitrate, tetracene and lead oxide along with others.
U.S. Pat. No. 4,412,492 utilizes lead nitrate along with tetracene and other oxides.
U.S. Pat. No. 4,432,819 utilizes lead nitrate with others.
U.S. Pat. No. 4,608,102 utilizes DDNP, tetracene and manganese dioxide.
U.S. Pat. No. 3,420,137 utilizes tetracene, PETN and aluminum along with others.
U.S. Pat. No. 5,167,736 utilizes DDNP, strontium nitrate, tetracene and calcium carbonate along with other elements such as as boron.
U.S. Pat. No. 5,216,199 utilizes DDNP, tetracene along with strontium nitrate.
U.S. Pat. No. 4,363,679 utilizes zinc oxide along with PETN and nitrocellulose.
U.S. Pat. No. 4,675,059 utilizes DDNP along with manganese dioxide and tetracene.
U.S. Pat. No. 4,581,082 utilizes zinc dioxide along with strontium and others.
EPO Patent No. 58048681 utilizes cupric oxide along with tetracene, calcium silicide and other materials.
The closest prior art within our knowledge is believed to be U.S. Pat. No. 3,707,411 which utilizes the combination of DDNP or tetracene, nitrocellulose, and PETN (pentaerythritol tetranitrate). This patent advocates the use of a single percussion-sensitive compound selected from the group consisting of a diazo, a triazole, and a tetrazole compound in combination with a mixture of nitrocellulose. It does not utilize a metallic oxidizing compound, but it discloses and claims the use of a single percussion-sensitive compound in combination with nitrocellulose and expressly specifies the exclusion of calcium silicide. As a consequence, the performance of the composition disclosed and claimed therein, as shown by tests which we have conducted, is less desirable than the performance accomplished through the use of our non-toxic composition as defined and claimed herein.